A known form of storage medium for use in storing computer data takes the form of a magnetically writable and/or recordable tape that is moved relative to magnetic transducer (read and/or write) heads for transferring data between the apparatus and the tape. One form of magnetic tape data transfer apparatus is a tape drive that comprises a rotary-scan tape deck in which the tape from a tape cartridge passes at a predetermined angle across a rotary head drum. In operation the tape is drawn from a supply reel to a take-up reel by rotation of a capstan against which the tape is pressed by a pinch roller. The head drum houses two write heads angularly spaced by 180° and two read heads also angularly spaced by 180°.
The magnetic tape is subject to wear and deterioration and the data transfer apparatus is subject to head clogs. The result is that errors occur in the read/write process. Whilst some errors can be detected and/or corrected by a format of data encoding that includes error control within the format definition, nevertheless it is necessary to take steps to clean the transducer heads so that errors that are attributable to dirty heads are eliminated or reduced.
It is already known to clean the magnetic transducer heads by inserting a cleaning tape cartridge into such a magnetic data transfer apparatus. The cleaning tape cartridge contains a cleaning tape that has no written data but is pulled through the data transfer apparatus to clean the heads. The cleaning tape is advanced by a chosen increment to clean the heads. The increment of cleaning tape that is pulled through the data transfer apparatus is contaminated by the cleaning process and is not re-used. A fresh increment of the cleaning tape is advanced when a cleaning operation is performed the next time.
A disadvantage of known methods of cleaning the heads of the data transfer apparatus by a cleaning tape is that, in a situation where an unsatisfactory cleaning operation has resulted, it can be unclear to a field user that the heads are still in an unsatisfactory state, and/or whether a further clean, perhaps with different cleaning parameter values, is advisable and likely to further improve the error rate. Field users of the data transfer apparatus also sometimes do not accurately follow instructions for carrying out cleaning of the transducer heads, which can result in unnecessary reporting of faults that can be remedied merely by cleaning the heads. Furthermore, where field users do carry out predetermined cleaning routines for remedying poor data transfer performance, these routines might not be entirely appropriate for the situation. For example, predetermined cleaning routines can be unnecessarily extensive, resulting in wastage of or undue wear to the cleaning tape.
It is an object of the invention to mitigate or overcome at least one of the above-mentioned problems.